Natural cartilage surfaces were macroscopically curved with multi-porous viscoelastic biologic materials with extremely high water, but whether curved surface configuration could play an important role on the contact and frictional properties of natural cartilages fails to be completely understood up to now. In this current study, cartilage samples came from the 18-24 month-old bovine femora. Contact characteristic and frictional properties at two cartilage configurations were investigated using the UMT-2 testing rig and the five-point sliding average method would be adopted to analyze these tested data. These results indicated the surface displacement was extremely associated with the plate cartilage surface and seemed to be a representative of cartilage surface configuration. The summit of the surface load lagged behind that of the surface displacement at the same condition. Coefficient of friction showed obviously different variation with time at two cartilage surface configurations due to the fact that these two surface displacements had different amplitudes and opposite directions as a function of the sliding length. Therefore, surface configuration played the main role on these variables of contact displacement, contact load and coefficient of friction due to the direction and magnitude of the surface displacement while applied load and sliding velocity had a secondary role. Natural cartilage surfaces were macroscopically curved with multi-porous viscoelastic biologic materials with extremely high water, but whether curved surface configuration could play an important role on the contact and frictional properties of natural cartilages fails to be completely understood up to now. In this study, two different cartilage configurations were adopted to investigate natural cartilage properties, and the five-point sliding average method would be used to analyze these tested data. These results indicated the contact displacement was consisted of cartilage deformation and surface displacement while contact load was composed of steady load and surface load (as shown in the figure, panels (a) and (b)). Surface displacement was greatly associated with the plate cartilage surface and seemed to be a representative of cartilage surface configuration. These two surface displacements had different amplitudes and opposite directions as a function of the sliding length (as shown in panel (c)). The summit of the surface load lagged behind that of the surface displacement at the same condition (as shown in panel (d)). Surface displacement and surface load in the contact characteristic of natural cartilages were extremely related with the cartilage configurations. and their correlation coefficients varied periodically with the moving time (as shown in panel (e)). Coefficient of friction showed obviously different variation with time (as shown in panel (f)). Therefore, surface configuration played the main role on these variables of contact displacement, contact load and coefficient of friction due to the direction and magnitude ...
A kind of slurry which is applicable for fine atomizing CMP was made and the optimal results were obtained through orthogonal experiments by comparing fine atomizing CMP and traditional CMP. The research results show that the material removal rate of fine atomizing CMP is 52.23% of traditional CMP, and the dosage of the slurry used in fine atomizing CMP only accounts for 10 vol% compared to traditional CMP. The surface roughness after the fine atomizing CMP is 2.5nm which is better than that of the traditional CMP (3.0nm).
The Diamond-like carbon coating (DLC) was derived by the PVCD method on the 45 steel surfaces. The frictional properties and fatigue failure of 45 steel with the DLC films were investigated under three different conditions including full contact condition, horizontal reciprocating movements and vertical reciprocating movements. It was found that (a) at full contact conditions: the increase in the load leads to the initial decrease in the frictional coefficient and then increase, and a lowest frictional coefficient of 0.205 appears at 250N; (b) at horizontal reciprocating conditions: the slow decrease in the frictional coefficient was caused by the increase in load, and frictional coefficients of 0.213 and 0.178 appears at 100N and 300N, respectively; (c) at vertical reciprocating conditions: the frictional coefficient was initially enhanced and then followed by a decrease trend; the highest frictional coefficients of 0.640 appears at load of 200N. The wear rate was slightly enhanced as the load is lower than 200N, and was sharply increased with the further increase in the load. The lowest wear rate was 1.55 mg/10000r, and the highest wear rate was 15.6mg/10000r.
Tin dioxide (SnO2) nanoparticles have been synthesized in bulk quantity by thermal evaporation of SnO powder. The x-ray powder diffraction (XRD) analysis indicates that the nanoparticles are the tetragonal rutile structure of SnO2. Scanning electron microscopy (SEM) analysis shows that the size of the synthesized SnO2 nanoparticles is relatively homogeneous with diameter of about 10 nm. Gas-sensing components have been manufactured with the SiO2 nanoparticles. Their performances indicate that it has high sensitivity and selectivity to LPG, and the max sensitivity appears at 280°C, compared with C2H5OH, H2, CO and CH4.
Tadpole-like microstructures which consisted of silica nanowires have been synthesized on Si wafers at 950°C by using tin droplets as catalyst. Each tin droplet can simultaneously catalyzes the growth of many silica nanowires of each tadpole-like microstructure and can simultaneously catalyzes the growth of even two tadpole-like microstructures, which is quite different from the conventional vapor-liquid-solid process. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses show that the tadpole-like microstructures with diameters of 5 μm and lengths of up to 50-100 μm. The amorphous silica nanowires with a composition close to that of SiO2have diameters of 100–200 nm. The PL spectra of the SiO2nanowires shows a strong emission peak centered at 390 nm (3.18 eV), while two weak PL peaks at 323 nm (3.84 eV), and 455 nm (2.73 eV) can also be observed. The growth mechanism of the tadpole-like microstructures was also investigated.
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